It is known to have a conveyor system with moving buckets supported by, and capable of being stopped at, a pre-determined position for a pre-determined period of time in the vicinity of a station. While a bucket is stationary it is possible, for example, for load items to be loaded or unloaded from the bucket. In such a system, the buckets are driven by a continuous means which engages the buckets through a simple clutch mechanism. When it is desired to stop a bucket, an abutment device is brought into contact with the bucket which temporarily prevents movement of the bucket along the conveyor support. The clutch mechanism between the bucket and the continuous means slips as the abutment device overrides the continuous means.
This known type of bucket conveyor system has disadvantages. There is considerable wear on the clutch mechanism when the bucket is stopped because the clutch mechanism is not disengaged but rather just slips. The friction wear on the clutch mechanism necessitates frequent replacement of parts. Also, in this known bucket conveyor system, the bucket is brought to an abrupt stop when the abutment device is brought into contact with the bucket. This will cause loose items carried by the bucket to be thrown about within the bucket. The speed at which the conveyor system can operate will thus be limited so as not to result in the disarrangement of items in the bucket during the abrupt deceleration. Also, when the abutment device is removed from contact with the bucket, the continuous means will no longer be overridden and the bucket will accelerate to the speed of the continuous means. However, the characteristics of the acceleration of the bucket will depend largely on the clutch mechanism and the acceleration will be abrupt.
Also, in a bucket conveyor system a plurality of buckets which are moving on the conveyor support are spaced a desired distance apart (the "pitch"). As explained above, in the known systems, once the abutment device is removed from contact with a bucket, the bucket will accelerate to the speed of the continuous means. However the characteristics of the acceleration of a bucket will depend partly on the particular clutch mechanism associated with that bucket. In a conveyor system having a plurality of buckets, the characteristics of each of the clutch systems will not be identical, and therefore the characteristics of the acceleration of each bucket will not be identical. Therefore, even if every bucket is stopped for the same pre-determined period of time, there will be an inconsistent spacing of buckets once the buckets are moving again along the conveyor support.
The present invention overcomes the disadvantages of the known conveyor systems by providing for an engaging element driven and supported by a continuous carrying means. The engaging element engages the bucket and drives the bucket along a bucket support. When it is desired to stop the bucket, the engaging element is disengaged from the bucket. Furthermore the invention may provide a path for the engaging element so that the engaging element decelerates the bucket in a progressive manner, and further, at the point of disengagement of the engaging element, the bucket is stationary on the bucket support.
The engaging element then moves along a path and remains disengaged from the bucket for the desired predetermined period of time, after which the bucket is re-engaged. Once the engaging element has re-engaged the bucket, the bucket will accelerate and commence moving again along the bucket support. Furthermore the invention may provide a path for the engaging element, such that upon re-engagement, the acceleration of the bucket is smooth and not abrupt.